Wire reinforced corrugated board and method and apparatus for making same

ABSTRACT

A reinforced laminate and the method and apparatus for the manufacture thereof which includes the embedding of reinforcing wire elements in plastic layers and plastic laminates to provide reinforced structures, producing a reinforced corrugated laminate including a corrugated layer with plastic layers applied to one or both sides thereof, producing a wire grid, corrugating the grid and applying overlying plastic layers and combining the planar and corrugated structures with cushioning and resilient foam materials.

This application is a continuation of Application Ser. No. 913,242 filedJune 6, 1978, now U.S. Pat. No. 4,228,209, entitled "Wire ReinforcedCorrugated Board and Method and Apparatus for Making Same" which is acontinuation of Application Ser. No. 771,993 filed Feb. 25, 1977entitled "Method and Apparatus for Making Reinforced Laminated andCorrugated Materials" now abandoned which was a continuation ofApplication Ser. No. 551,978 filed Feb. 21, 1975 entitled "Method andApparatus for Making Reinforced Laminated and Corrugated Materials" nowabandoned.

This invention relates to reinforced plastic sheet material in bothsubstantially planar and corrugated form and to novel and improvedmethods and apparatus for manufacturing such materials. The inventionfurther relates to the lamination of the aforesaid reinforced plasticsheets with other resilient and cushioning materials which areparticularly suited among other applications for packaging articles forshipment.

This invention has as one of its objects the provision of a novel andimproved corrugated material formed of plastic sheets and relativelystiff wire reinforcing elements which is not only moistureproof but alsomay be made impervious to gases and which will neither deteriorate norweaken even when constantly subjected to moisture. Depending upon theapplication, the reinforcing elements may either be coated with aplastic or uncoated and are preferably in the form of longitudinal andtransverse elements secured in spaced relationship to form a structureaffording substantial strength in the finished material. Moreover,reinforcing elements of a variety of diameters and plastic layers ofvarious thicknesses may also be utilized depending upon the strength andstiffness desired.

Another aspect of the invention involves an improved plastic sheetmaterial having longitudinal and transverse wires embedded therein toprovide materially added strength and at the same time protect the wiresfrom corrosion or deterioration from water and gases. The sheet materialmay be either a single layer or laminate or be in the form of acorrugated structure with plastic layers on one or both sides thereof.

Another object of the invention resides in the provision of novel andimproved methods and apparatus for fabricating reinforced sheet andcorrugated plastic materials having reinforcing elements of wireembedded therein.

Still another object of the invention resides in the provision of anovel and improved method and apparatus for forming a grid oflongitudinal and transverse reinforcing elements and embedding them in aplastic sheet.

A still further object of the invention resides in the provision of anovel and improved method and apparatus for forming a grid oflongitudinal and transverse wires, corrugating said grid and applyingoverlying layers of plastic to form a relatively rigid board ofappreciable thickness with substantially complete resistance tomoisture.

A still further object of the invention resides in the provision of anovel and improved method and apparatus for forming a corrugated boardof plastic material having a corrugated grid of longitudinal andtransverse wires with overlying layers of plastic sheets having wiregrids embedded therein.

A further object of the invention resides in the provision of animproved material comprising a wire reinforced plastic sheet structurelaminated with resilient and cushioning materials.

This invention concerns the formation of improved plastic materialswherein a reinforcing grid in either flat or corrugated form is combinedwith plastic sheet material to form a reinforced plastic sheet orstructure of appreciable thickness wherein the grid is corrugated andlies between two sheets of plastic. The corrugated grid may be coatedwith a plastic or may be uncoated and the overlying plastic sheets mayalso be reinforced with grids. The improved plastic materials may alsobe laminated with resilient and cushioning sheet materials for packagingand other purposes. Formation of the plastic materials involves both animproved method and apparatus whereby the sets of longitudinal andtransverse elements of wire arranged in perpendicular grid-likerelationship are embedded individually or simultaneously in plastic toform a reinforced sheet. The sets of elements whether embedded orunembedded may then be corrugated and enclosed by overlying plasticsheets sealed to the corrugated structure. If desired, the overlyingsheets may also be reinforced by wire. Resilient or cushioning materialmay also be sealed to either the reinforced plastic sheet or thecorrugated structure.

The above and other objects of the invention will become more apparentfrom the following description and accompanying drawings forming part ofthis application.

In the drawings:

FIG. 1 is a diagrammatic view of the apparatus for forming a plasticlaminate having longitudinal wires disposed therein.

FIG. 1A is an enlarged cross-sectional view of the laminate with thereinforcing wires disposed therebetween at an initial stage in theformation of the product;

FIG. 1B is a cross-sectional view of FIG. 1A taken along the line 1B--1Bthereof;

FIG. 1C is a cross-sectional view of the completed laminate;

FIGS. 1B' and 1C' correspond to FIGS. 1B and 1C respectively and showmore precisely the relative thickness of the plastic layers andreinforcing wire elements.

FIG. 2 illustrates a modified embodiment of the invention wherein thereinforced laminate is formed by the utilization of an adhesive;

FIG. 2A is an enlarged cross-sectional view of the laminate at aninitial stage in the formation thereof;

FIG. 2B is a cross-sectional view of FIG. 2A taken along the line 2B--2Bof FIG. 2A;

FIG. 2C shows the completed structure;

FIG. 3 is a plan view of one form of apparatus for feeding wires intothe laminates of FIGS. 1 and 2;

FIG. 4 illustrates apparatus for producing a reinforced plastic sheet inaccordance with the invention;

FIGS. 4A and 4B are cross-sectional views of two stages in the formationof the reinforced plastic sheet produced by the apparatus of FIG. 4;

FIG. 5 illustrates still another embodiment of the invention for forminga wire reinforced laminate;

FIG. 5A is a cross-sectional view of an initial stage in the formationof the laminate by the apparatus shown in FIG. 5;

FIG. 5B is a cross-sectional view of FIG. 5A taken along the line 5B--5Bthereof;

FIG. 5C is a cross-sectional view of the complete laminate formed by theapparatus of FIG. 5;

FIG. 6 is a modified form of the apparatus shown in FIG. 5 utilizing anadhesive for forming the wire reinforced laminate;

FIG. 6A is a cross-sectional view of an initial state in the formationof the laminate with the apparatus of FIG. 6;

FIG. 6B is a cross-sectional view of FIG. 6A taken along the line 6B--6Bof FIG. 6A;

FIG. 6C shows the completed laminate;

FIG. 7 illustrates an embodiment of the invention for forming a laminatehaving both longitudinal and transverse reinforcing wires;

FIG. 7A is a cross-sectional view of the reinforced laminate formed withthe apparatus of FIG. 7;

FIG. 7B is a cross-sectional view of FIG. 7A taken along the line 7B--7Bthereof;

FIG. 7C is a view similar to FIG. 7B showing more precisely the relativethicknesses of the plastic layers and reinforcing wires.

FIG. 8 illustrates apparatus for forming a plastic laminate having bothlongitudinal and transverse reinforing wires wherein the laminateutilizes an adhesive for joining the layers;

FIG. 8A is a cross-sectional view of the complete laminate formed by theapparatus of FIG. 8;

FIG. 8B is a cross-sectional view of FIG. 8A taken along the line 8A--8Athereof;

FIG. 9 illustrates apparatus for foming a corrugated laminate materialhaving reinforcing wires embedded therein;

FIG. 9A is a cross-sectional view of an initial step in the formation ofthe laminate corrugated material produced by the apparatus of FIG. 9;

FIG. 9B is a cross-sectional view of one form of the completed laminatecorrugated material produced by the apparatus of FIG. 9;

FIG. 9C is a cross-sectional view of a modified form of material shownin FIG. 9B;

FIG. 10 is a modified form of the apparatus shown in FIG. 9 wherein theouter layers of material are joined to the corrugated material by meansof an adhesive;

FIG. 10A is a cross-sectional view of the material produced by theapparatus of FIG. 10;

FIG. 10B is a cross-sectional view of a modified form of materialproduced by the apparatus of FIG. 10;

FIG. 11 illustrates one procedure in accordance with the invention forforming a wire grid for use in making corrugated reinforced plasticmaterial;

FIG. 11A is a cross-sectional view of the wire grid produced inaccordance with the apparatus of FIG. 11;

FIG. 12 illustrates apparatus for forming a corrugated laminatedmaterial utilizing a wire grid, as for instance the grid shown in FIG.11A;

FIG. 12A is a cross-sectional view of the product produced by theapparatus of FIG. 12;

FIG. 13 is a modified embodiment of the invention for producing alaminated corrugated reinforced plastic material in accordance with theinvention;

FIGS. 13A, B and C are cross-sectional views of successive stages in theformation of the product produced by the apparatus shown in FIG. 13;

FIG. 13D is a cross-sectional veiw of the completed material formed bythe apparatus of FIG. 13;

FIG. 13E is a modified form of material produced by the apparatus ofFIG. 13;

FIG. 13E' is similar to FIG. 13E showing the thicknesses of the plasticlayers and reinforcing elements more precisely.

FIGS. 14 and 15 show combinations of reinforced plastic materials withcellular material and foam respectively; and

FIGS. 16 and 17 show combinations of reinforced corrugated materialswith cellular material and foam respectively.

As pointed out above, the improved product comprises a plastic sheet orlaminate having reinforcing wires disposed therein or in the alternativemay comprise a coated or uncoated corrugated wire grid having layers ofplastic on one or both sides thereof. One method and apparatus forforming reinforced plastic sheet material in accordance with theinvention is shown in FIGS. 1 and 1A through C. While the resultantproduct produced by the apparatus of FIG. 1 as well as the productsproduced by the apparatus shown in FIGS. 2, 4, 5 and 6 are useful formany purposes, it will be shown that such products are also useful inthe formation of other types of reinforced products in accordance withthe invention for structural, packaging and other similar applications.

Reference is now made to FIG. 1 which illustrates one embodiment of theinvention for fabricating a plastic laminate having longitudinalreinforcing wires embedded therein. More specifically, the apparatusincludes a relatively large heated drum 10 onto which the first film 11which may be precoated with a heat sensitive adhesive, is fed from theroll 12 and about roller 13. If desired, the roller 13 may also beheated in order to increase the temperature of the film 11 just prior toits engagement with the drum 10. Immediately following the applicationof the film 11 to the drum 10, a plurality of wires 14 are fed from aplurality of spools 15' about rollers 15 and 16 and onto the drum 10 andin overlying relationship with film 11. The roller 16 is preferablyprovided with a plurality of spaced, annular, wire receiving grooves tomaintain the desired wire spacing. The roller 15 which initially spacesthe wires will be described in detail in connection with FIG. 3.

A second film 17, which may be pre-coated with a heat sensitive adhesiveis fed from a roll 18 and about the roller 19 in overlying relationshipwith the wires 14. The laminate then proceeds about the drum 10 andsufficient heat is applied to the laminate so that the two films can besealed one to the other with the wires therebetween. The temperature ofthe drum 10 is, of course, related to the speed so that adequate heat istransferred to the plastic films. For instance, if the drum 10 isrotating at a relatively high speed the temperature of the drum can beat or even above the melting point of the plastic film 11. On the otherhand, should the drum be operated at a low speed it would be necessaryto maintain the temperature of the drum slightly below the melting pointof the film 11.

The two films are sealed one to the other by a pressure roller 20preferably covered with a thin layer of polytetrafluorethylene in orderto prevent any possible adherence of the film to the pressure roller.The coating of the roller 20 is denoted by the numeral 20' and theroller 20 is preferably cooled by engagement with a cooling roller 21since it is important that the surface of the roller be maintained at atemperature well below the melting point of the plastic and preferablybelow the embossing temperature. The roller 20 also functions to removethe completed laminate from the roller 10 whereupon it is fed aboutcooling rollers 22 and 23 and then wound upon a spool 24. FIG. 1A showsa longitudinal section through the laminate prior to the sealing of thefilms 11 and 17 one to the other. FIG. 1B shows a transverse view of thelaminate prior to sealing of the layers, while FIG. 1C is a transverseview showing the two layers sealed one to the other with the wires 14disposed therein. In actual practice each of the films is normally aboutone half the thickness of the wires and a more accurate representationof the product is shown in section in FIGS. 1B' and 1C.

It is evident from the description of the apparatus in FIG. 1 that if itis desired to use a single film such as the film 11 and merely embed thewires 14 in the surface thereof the wires may be coated with a primersuch as sodium silicate, for instance, or may be coated with a very thinlayer of a suitable plastic in order to facilitate adherence of the wireto the film 11. In such a case the wires whether including a primer andthe coating of plastic or just the plastic coating itself would be fedonto the surface of the film 11 as shown in FIG. 1 and thereafter thepressure roller 20 would force the wires into the surface of the film.

In feeding the wires 14 into overlying relationship with the film 11 itmay be desirable or necessary to maintain a predetermined tension on thewires. For this purpose an auxiliary roller 16' may be utilized whichbears against the grooved roller 16 and by the utilization of brakingmeans on the roller 16' the tension on the wires can be controlledaccurately.

A modified form of the invention shown in FIG. 1 is illustrated in FIG.2. In these figures like components are denoted by like numerals. In theform of the invention shown in FIG. 2 the film 11 is fed from a spool 12and thence onto a roller or drum 25 by means of an intervening idlerroller 26. An adhesive contained in a trough 27 is applied to the outersurface of the film 11 by means of applicator rollers 28 and 29whereupon the coated film passes through drying means 30 which may be inthe form of an electric heater or in the alternative may be in the formof a housing having an inlet 31 and an outlet 32 for feeding hot airthrough the housing and over the surface of the film. The dried film isthen fed about the rollers 33 and 34 to the drum 10. The remainder ofthe process is identical to that of FIG. 1 except that the temperatureof the roller 10 can be modified so that it will adequately heat theheat sensitive adhesive in order to provide a seal between the films 11and 17. If desired, the film 17 may be coated in a manner similar to thefilm 11 so that the meeting surfaces of both films are coated with heatsensitive material in order to facilitate formation of a sealtherebetween. FIG. 2A shows the initial relationship of the wires 14,the adhesive coated layer 11 and the non-coated layer 17. FIG. 2B is across-sectional view of 2A while FIG. 2C shows the complete structurewith the adhesive 11' between the two layers.

It is evident that a wide variety of plastic materials may be used toform the sheets 11 and 17 and the selection of the specific plasticwould then, in a large part, depend on the ultimate use for the product.For instance, it may be desirable to use films having differentcharacteristics as well as different colors for decorative purposes andthe films may either be thermoplastic or thermosetting. When substantialstrength is desired particularly when the product is to be used in hightemperature or structural applications a thermosetting plastic isdesired. Such a thermosetting plastic should, of course, have athermoplastic stage and then ultimately assume a thermosetting stage inthe final product. It is also evident that the plastic layers may havesubstantial flexibility for certain applications while in otherapplications relatively rigid plastics may be utilized.

In providing a product for specific application to the packagingindustry, plastics such as polyethylene, polystyrene, high densitypolyethylene, polypropylene, as well as the polyamides and thepolyesters are probably the more desirable plastics that can be used.

While the wires 14 may be guided onto the drum 10 in any suitablemanner, one form of apparatus which may be used for this purpose isillustrated in FIG. 3. In this figure the roller 15 which guides thewires onto the roller 16 is provided with a plurality of closely spaceddiscs 35 which maintain the spacing between the wires 14. The wires arefed from a plurality of spools 15' through a series of guides 36 whichlead the wires between the discs on the roller 15. With this arrangementthe roller 16' would be provided with a resilient surface and bearagainst the wires 14 while on the roll 16. With such an arrangementtension would effectively be controlled and it would not be necessary torely solely on the friction of the wires with the roller 16 in order tocontrol the tension.

FIG. 4 illustrates a further modification of the invention wherein aplastic material is extruded directly onto a drum and in contact with aplurality of longitudinally disposed reinforcing elements such as wires.In this embodiment of the invention, drum 37 is preferably cooled by thecirculation of water or other suitable coolant therethrough and aplurality of wires 14 are fed from a plurality of spools 15' via theroller 16 to the surface of the drum 37. The drum 37 may or may not havea plurality of fine grooves for the receipt of the wires 14. In mostcases however it would not be necessary to groove the drum providedadequate tension is maintained on the wires. Immediately after feedingthe wires onto the drum 37 a plastic material 38 is extruded onto thedrum by an extruder 39 which may preferably be a straight-die extruder.Since the plastic extruded onto the surface of the drum is at a veryhigh temperature it will surround the wires as illustrated in FIG. 4Aand then will gradually cool until it reaches the take-off roller 40.The roller 40 is cooled in order to reduce the temperature on the sheetso that it can be fed about the roller 41 and then wound on spool 42.The complete product is shown in FIG. 4B and is then ready for eitherfurther processing or direct use for the desired purpose. The form ofthe invention shown in FIG. 4B is substantially identical to the productpreviously described in connection with FIG. 1 wherein a single film 11is utilized and the wires 14 are embedded in the surface of the film. Itis also understood in connection with FIG. 4 that the wires 14 may beeither coated or uncoated as desired.

A further embodiment of the invention is illustrated in FIG. 5. In thisembodiment of the invention a film 43, which may be pre-perforated, isfed from a spool 44 about a roller 45 onto a drum 46. Immediatelyfollowing the application of the film 43 a plurality of wires 47 are fedfrom spools 15', about rollers 48 and 48' and onto the surface of theperforated film 43. The rollers 48 and 48' correspond essentially to therollers 15 and 16 of FIG. 1. A second unperforated film 49 is fed from aspool 50 about a roller 51 and into overlying relationship with thelongitudinally disposed wires 43. The structure of the product at thispoint in the process is shown in FIG. 5A which illustrates therelationship of the films 43 and 49 with the wires 47 disposedtherebetween. The perforations in film 43 are denoted by the numeral43'. FIG. 5B is a cross-sectional view of FIG. 5A.

The laminate denoted by the numeral 53 then moves downwardly betweenheaters 52 and about a roller 54 which has vacuum ports distributedthroughout the surface thereof and is also cooled by the circulation ofthe coolant therethrough. The specific structure of the roller 54 iswell-known in the art.

Heat imparted to the laminate 53 by the heaters 52 is sufficient toenable production of an adequate seal between the films 43 and 49 withthe wires disposed therebetween. If desired, a pressure roller 55 may becoordinated with the roller 54 to insure an adequate seal. The films 43and 49 with the wires 47 disposed therebetween are then further cooledby roller 56 whereupon they are fed about a roller 57 and wound upon thespool 58. The resultant product is shown in cross-section in FIG. 5C,though in actual practice the thickness of the combined plastic layersmay not exceed the thickness of the wires.

The form of the invention shown in FIG. 6 is substantially identical tothat form illustrated in FIG. 5 except that one of the plastic sheets iscoated with a heat sensitive adhesive prior to lamination with the otherlayer. Accordingly, in these two figures, like numerals are utilized todenote like components. In this embodiment of the invention film 43 isfirst fed onto the roller 46 in the manner described in connection withFIG. 5 whereupon the longitudinal wires are fed into overlyingrelationship with the film. The film 49 is fed from a spool 50 aboutrollers 59 and 60 and thence onto the drum 61. An adhesive contained inthe trough 62 is applied to the surface of the film 49 by rollers 63 and64 whereupon the film then travels about the roller 61 and is dried by aradiant heater 65 and/or hot air as desired. The coated film then leavesthe roller 61 and is fed about the roller 50 and onto the roller 46 inoverlying relationship with the wires to produce an initial laminatedenoted by the numeral 53 and illustrated in section in FIGS. 6A and 6B.The preliminary laminate passes between heaters 52-52 and thence aboutthe cooled vacuum roller 54 which by reason of the perforation of thefilm 43 produces adherence of the two films one to the other. Inasmuchas the heat sensitive adhesive is utilized the temperature of the films,in order to effect sealing, would not need to be as high as in the caseof the apparatus shown in FIG. 5 with the result that one of the films,namely, film 49 would be slightly deformed to lie closely about thewires 47 as shown in FIG. 5C. In this figure the adhesive is denoted bythe numeral 49'. If desired, in order to provide a more effective seal,a pressure roller 55 may be utilized in combination with the roller 54in which event the resultant product would take more nearly the formshown in FIG. 5C of the drawings. In FIGS. 6A to C the thickness of thefilms have been enlarged for illustrative purposes.

In the previous embodiments of the invention a laminate was formedutilizing a plurality of longitudinal wires with a layer of plastic oneither one or both sides of the wires as the case may be. It is evidenthowever that if desired in the previous embodiments of the invention oneof the films may be previously formed with wires extending transverselythereof so that the resultant product would have both transverse andlongitudinal wires disposed therein and thus form in effect a gridenclosed in a plastic. It is also evident that various sizes of wire andvarious thicknesses and types of plastic materials may be employeddepending on the use of the resultant product.

FIGS. 7 and 8 illustrate two forms of the invention for producingresultant products having both longitudinal and transverse wiresembedded in plastic sheets. While any number of procedures may beutilized in forming a plastic sheet with transverse wires therein onesuitable procedure involves the utilization of a product such as shownin FIG. 1C, 1C', 2C, 4B, 5C or 6C and cutting them to lengths equivalentto the width of the sheet. Each severed portion is rotated 90° and thensuccessive such portions secured together by heat sealing or othersuitable means to provide an elongated roll of film wherein wires extendtransversely of the film. Such a structure may be utilized in connectionwith FIG. 7.

The apparatus of FIG. 7 includes a drum 69 having vacuum portsdistributed over the surface thereof and means for the circulation of asuitable fluid therethrough for controlling the temperature of the drum.This is desirable inasmuch as heating means are provided about the drumas will be described in order to raise the temperature of the films forthe purpose of lamination. A first film denoted by the numeral 70 is fedfrom a spool 71, about a roller 72 and onto the drum 69. Thereafter aplurality of longitudinal wires 73 are fed from a plurality of spools15' about rollers 74 and 75 into overlying relationship with the film70. The rollers 74 and 75 correspond essentially to rollers 15 and 16 ofFIG. 1. A perforating drum 76 having a plurality of tines extendingtherefrom perforate the film 70 so that the vacuum produced within thedrum 29 will cause the film to adhere closely to the surface of thedrum. The film 70 together with the wires 73 then passes beneath theheater 77 which raises the temperature of the film and the wires to apoint close to the melting point of the film. A second film 78 is fedfrom a spool 79 and about the roller 80 into overlying relationship withthe wires 73 and thence past the heater 81 that imparts heat to theouter film and raises it to a temperature required for sealing it to thefirst film 70.

One or the other of the films 71 and 78 contains transverse wires andthe film may be produced in a manner previously described. The heatedstructure then passes between the nip of drum 69 and roller 82 in orderto effect the seal between the two films and the sealed films then passabout the roller 82 and then about rollers 83 and 84. Rollers 82 through84 also function to cool the laminate so that the resultant laminate 85is ready to be rolled upon a spool or carried to subsequent processingapparatus. The resultant laminate 85 is shown in FIGS. 7A and 7B. Inthis case the film 70 has a plurality of wires 70' and the wires 73 aredisposed between the film 70 and the film 78. A cross-sectional view ofthe structure shown in FIG. 7A is illustrated in FIG. 7B. FIG. 7C issimilar to FIG. 7B and shows more precisely the relative thicknesses ofthe plastic layers and wires.

The structure shown in FIG. 8 differs from the structure shown in FIG. 7in that an adhesive is utilized in order to secure the two plasticsheets one to the other. In this form of the invention a drum 69substantially identical to the drum described in connection with FIG. 7is utilized and the first film 70 is fed from a spool 71 and about theroller 72 onto the drum 69. A plurality of wires 73 are then fed from aplurality of spools 15' and about the rollers 74 and 75 into overlyingrelationship with the film 70. The wire 73 and film 70 are then fedbeneath the heater 77 to bring the film and the wires up to a sealingtemperature. The film 78 is fed from a spool 79 about a roller 80 andonto a drum 86 having heating means 87 disposed about a portion of theperiphery thereof. An adhesive contained in the trough 88 is fed bymeans of rollers 89 and 90 to the outer surface of the film 78 and thecoated film is then dried by the heater 87 and is fed onto the drum 69in overlying relationship with the wires 73. Further heat is imparted tothe laminate on the drum 69 by the heater 81 to complete the sealbetween the two films with wires 73 disposed therebetween. As in thecase of FIG. 7 one or the other or the films 70 and 78 preferablyincludes transverse wires so that the resultant structure has bothlongitudinal and transverse wires forming in effect a grid embedded inthe plastic laminate. The complete laminate then passes about rollers82, 83 and 84 which are preferably cooled so that the resultant laminate85' is ready for further processing or storage as the case may be. Ifdesired the roller 82 may be in pressure engagement with the laminate asit passes between that roller and drum 69 in both FIGS. 7 and 8 toinsure uniform sealing of the layers. The resultant structure 85' isshown in FIG. 8A and includes the film 70 having wires 70' disposedtherein, a layer of adhesive 78' and a bottom layer of plastic 78. Thewires 73 are, of course, disposed between the layers. FIG. 8B is across-sectional view of FIG. 8A.

FIG. 9 illustrates an embodiment of the invention for producing areinforced corrugated laminate that may be used for the formation ofcartons and the like in the packaging of articles as well as forstructural elements. The resultant structure essentially comprises acorrugated portion having overlying layers on one or both sides thereof.The corrugated portion is preferably reinforced with transverse wiresthrough longitudinal wires may also be used and the overlying layers maybe similarly reinforced by longitudinal or transverse wires or both asthe case may be.

In this embodiment of the invention the first plastic sheet 91preferably pre-coated with an adhesive is fed from a spool 92 about aroller 93 and onto a drum 94. The drum 94 may be temperature controlledto impart heat to the film 91 to raise its temperature to the vicinityof the melting point. The film 91 may, of course, include transversewires as previously described in connection with the embodiment of theinvention shown in FIGS. 7 and 8 or it may be an unreinforced film.Thereafter a plurality of longitudinal wires 95 are fed from a pluralityof spools 15' and about rollers 96 and 97 (rollers 15 and 16 of FIG. 3)onto the drum 94 in overlying relationship with the film 91 in much thesame manner as described in connection with FIG. 3. A second film 98 isfed from a spool 99, about the roller 100 and onto the drum 94 inoverlying relationship with the wires 95. The film 98 may or may not beprovided with longitudinal reinforcing wires as described in connectionwith the film 91.

The laminate is then fed downwardly through a heater 101 and about therollers 102 and 103 to the corrugating rollers 104 and 105. If the film91 is perforated in the same manner as described in the embodiment ofthe apparatus shown in FIGS. 7 and 8 or if the film is pre-perforated,the roller 102 would then be provided with a multiplicity of vacuumports in the surface thereof with appropriate vacuum means connected tothe ports in a manner well-known in the art, and sealing would then beeffected on the vacuum roller. On the other hand if the film 91 is notperforated, rollers 102 and 103 could be positioned in close proximityone to the other to provide sufficient pressure to effect a satisfactoryseal. In either case, however, the roller 103 is preferably cooled tolower the temperature of the complete laminate prior to engaging thecorrugating rollers 104 and 105.

The resultant laminate denoted by the numeral 106, then passesdownwardly through a heater 107 to again raise at least the surfacelayers of the corrugate to a sealing temperature. A third film 108preferably pre-coated with an adhesive which may or may not containreinforcing wires is fed from a spool 109 and about rollers 110 and 111,the latter being heated in order to bring the adhesive on the surface ofthe film 108 to a sealing temperature. The heated film 108 is then fedabout a roller 112, which may also be heated and then into surfacecontact with the corrugated structure 106. A fourth and preferablypre-coated film 113 similar to the film 108, is fed from a spool 114 andabout the rollers 115, 116 and 117 into overlying relationship with theother side of the corrugated structure 106. The roller 116 is heated inthe same manner as described in connection with the roller 111 and ifdesired the roller 117 may also be heated in order to maintain thetemperature of the film 113 at the sealing temperature as in the case ofthe film 108.

The corrugated structure 106 together with the overlying layers 108 and113 is fed between a pair of cooling belts 118 and 119 with the belt 118being carried by cooled rollers 120 and 121 and the belt 119 beingcarried by cooled rollers 122 and 123. Belts 118 and 119 are insufficiently close proximity one to the other to apply pressure to thelaminate to insure sealing of the overlying layers to the corrugatedstructure 106 without substantially deforming it. The resultantstructure is denoted by the numeral 124 and is ready for furtherprocessing or use.

A cross-sectional view of the corrugated structure 106 is illustrated inFIG. 9A, the plastic layers having been enlarged in thickness forillustrative purpose. It will be observed that the film 91 includestransverse wires 91', longitudinal wires 95 and the plastic layer 98.The final structure 124 as shown in FIG. 9B includes the corrugatedsubstructure 106 having longitudinal and transverse wires and a pair ofoverlying layers of plastic 108 and 113. A modified form of theinvention is shown in cross-section in FIG. 9C and denoted by thenumeral 124'. In this form of the invention the structure 106 hasoverlying layers 108 and 113 as in the case of FIG. 9B, but alsoincludes transverse reinforcing wires 108' and 113'. It is, of course,evident that the overlying layers 108 and 113 may also include bothlongitudinal and transverse reinforcing wires, as shown for instance inFIG. 13E which will be described.

The form of the invention shown in FIG. 10 is similar to thatillustrated in FIG. 9 and like numerals are utilized to denote likecomponents. The formation of the corrugated laminated reinforcedstructure 106 is substantially identical to that illustrated anddescribed in connection with FIG. 9. The overlying layers however arecoated with an adhesive just prior to the application to the corrugatedstructure. More specifically the film 125 is fed from the spool 126about rollers 127 and 128 thence upwardly through an oven 129. A trough130 carries an adhesive which is applied to the film 125 by a roller131. The adhesive is dried in the oven 129 and then fed about therollers 132 and 133 into contact with one side of the corrugatedstructure 106. The apparatus for applying the second film 134 to theother side of the corrugated structure 106 is identical to thatdescribed above and like primed numerals are utilized to denote likecomponents. The corrugated structure 106 together with the two films 125and 134 are fed downwardly between cooling rolls 135, 135' and 136, 136'to cool the structure and insure good adhesion of the outer layers. Theresultant structure is denoted by the numeral 137 and is illustrated incross-section in FIG. 10A. In this figure the corrugated structure 106is identical to the illustrated in FIG. 9A and it includes the outerlayers 125 and 134 secured to the corrugated structure by adhesivelayers 125' and 134'. The outer layers 125 and 124 may includereinforcing wires as illustrated in 10B wherein the reinforcing wiresare denoted by the numeral 138 in the layer 125 and the numeral 139 inthe layer 134. Longitudinal reinforcing wires are also preferablyincluded in the outer layers as shown in FIG. 13E to be described.

The preceding embodiments of the invention such as the embodiments shownin FIGS. 1 and 4 through 10 may be made utilizing a wire grid in placeof the longitudinal wires in which event the provision of a plasticlayer having transverse wires embedded therein would not be necessary.Thus, in FIG. 9 for example, the films 91 and 98 would not needtransverse wires since a wire grid could be fed between the films inplace of merely the longitudinal wires 95. An improved method andapparatus for producing such a grid is illustrated in FIG. 11.

In FIG. 11 a transversely corrugated belt generally denoted by thenumeral 140 is carried by a pair of drums of which only one isillustrated and denoted by the numerals 141. Suitable means are providedfor cutting wires into predetermined lengths and feeding themindividually into the troughs of the belt 140. The wires denoted by thenumerals 142 are illustrated on the top side of the belt and move indirection toward the drum 141. A plurality of narrow belts 143 carriedby sets of rollers 144, 145 and 146 hold the wires 142 in position onthe corrugated belt 140 as it travels downwardly about the left side ofthe drum 141 is shown in FIG. 11. As each wire reaches the bottom-mostportion it is discharged onto a drum having a plurality of axiallyaligned hooks 148 disposed about the periphery thereof. As each of thewires 142 is discharged onto the drum 147 it is engaged by one set ofhooks and is therefore retained in position as the drum 147 rotates. Aset of longitudinally disposed wires, denoted by the numeral 149, arefed from a plurality of spools 15' in much the same manner described inconnection with FIG. 3. These wires are fed about the rollers 150 and151, corresponding to the rollers 15 and 16 of FIG. 3, and pass betweenthe nip of the roller and a second roller 152. The roller 152 ispreferably grooved to insure the maintenance of proper spacing betweeneach of the plurality of wires 149. Wires 149 then pass beneath theheating means 153 and about the roller 154 which has a resilient layer155 on the surface thereof and preferably includes a plurality ofgrooves formed therein in order to clear the axial arrays of hooks 148carried by the roller 147. The wires 149 ride about the surface of theouter layer 155 on the roller 154 and are urged into tight engagementwith each of the transverse wires 142 to form a grid. In the preferredembodiment however the wires 149 are coated with a heat sensitiveadhesive on plastic which will insure a firm union between the two setsof wires. The joined wires, which now form a grid, are carried about theroller 147 and are guided by the roller 156 onto the spool 156. It ispreferable, of course, that the drum 147 be cooled in order to rapidlylower the temperature of wires after they have been joined. Across-sectional view of the resultant grid is illustrated in FIG. 11Awherein the longitudinal wires 149 are shown gripping the transversewires 142. If both sets of the wires have been pre-coated with a plasticor suitable adhesive of the heat sensitive type it will facilitateformation of a structure wherein the wire grid is corrugated and thenoverlying layers are applied as will now be described in connection withFIG. 12.

In FIG. 12 a wire grid, denoted by the numeral 158, is fed from a spool159 and about a roller 160 to corrugated rollers 161 and 162. Thecorrugated grid, now denoted by the numeral 158', is fed through aheater 163 and thence downwardly between a pair of belts 164 and 165.The belt 164 is carried by a pair of rollers 166 and 167 while the belt165 is carried by a pair of rollers 168 and 169. The rollers 166 through169 are preferably cooled in order to maintain the belts at atemperature well below the melting point or embossing temperature of thefilms to be applied to the surface of the corrugated structure. A firstfilm of plastic 170 is fed from a spool 171 about roller 172 and ontothe outside of the belt 164 as it passes about the roller 166. A secondfilm 173 is fed from a spool 174 about the roller 175 and onto the belt165 as it passes about the top side of roller 168. Since the wires havebeen heated to a relatively high temperature in the heater 163 they willimpart sufficient heat to the films as they are pressed into engagementwith the wires by the rollers 166 and 168. At the same time the rollersacting through the belts 164 and 165 maintain the films 170 and 173 infirm engagement with the corrugated grid while the entire structure iscooled. The resultant structure denoted by the numeral 176 is shown inFIG. 12A. The corrugated grid is denoted by the numeral 158' and it willbe observed that the outer portions thereof are embedded in the outerlayers of plastic 170 and 173. In most cases when utilizing a wire grid,it is preferable to use coated wires in order to protect the metal fromcorrosion.

A still further modification of the invention is illustrated in FIG. 13and illustrates one method and apparatus for continuously producing acorrugated structure wherein a reinforced corrugated layer is firstproduced and then the overlying layers are successively applied. In thisfigure a plurality of longitudinal wires 180 are fed from a plurality ofspools 15' and about rollers 181 and 182 (which correspond to rollers 15and 16 of FIG. 3) onto a cooling drum 183 which may be cooled by thecirculation of water or other liquid coolant in the manner well-known inthe art. Immediately after the application of the wires a plastic layeris applied to drum 183 by an extruder 184. Thereafter a plastic sheet orfilm 185 is fed from a spool 186 and about a roller 187 into overlyingrelationship with the extruded layer 188. Inasmuch as the layer 188 isat a relatively high temperature it will encase the wires 180 and sinceit is at least at the normal sealing temperature it will adhere to thefilm 185 which is applied immediately after extrusion. The layer 185preferably comprises a film previously processed to combine it withtransversely positioned wires in the manner previously described. FIG.13A shows a cross-sectional view of the wires 180 immediately after thelayer 188 is extruded onto the drum 183 in overlying relationship withthe wires. FIG. 13B is a cross-sectional view of the structure after thefilm 185 is applied to the extruded layer 188. In this figure it will beobserved that the layer 185 includes transverse wires 185'. Thestructure is shown in FIG. 13B which is formed on the drum 183 is thenremoved by a roller 189 whereupon it passes through heating means 190and thence to a pair of corrugating rollers 191 and 192. The corrugatedstructure denoted by the numeral 193 passes about rollers 194, 195 and196 and is then fed onto a second cooling drum 197 by means of theroller 198. Preceding the application of the structure 193 to the drum197, a second extruder 199 feeds a plastic layer 200 onto the drum 197.While the drum 197 is cooled in the same manner as drum 183,nevertheless the plastic layer 200 is at a relatively high temperatureand therefore upon the application of the corrugated structure 193 itwill firmly adhere to the layer 200. The resultant structure is shown incross-section of FIG. 13C and is removed from the drum 197 by a roller201 and is then fed about rollers 202 and 203 onto the drum 204. Priorto the application of the corrugated structure, with a layer of plasticapplied to one side thereof, to the drum 204 a third extruder 205applies a plastic layer 206 to the drum. This plastic layer forms asecond overlying layer for the corrugated structure. Since the extrudedlayer 206 is at a high temperature when the corrugated structure isapplied it will firmly adhere to the structure whereupon the layer 206is cooled by the drum 204 in the same manner as the layers 188 and 200were cooled by the drums 183 and 197. The resultant structure is thenremoved by roller 207 and the final material is denoted by the numeral208.

A cross-sectional view of the resultant structure 208 is shown in FIG.13D which shows the relative positions of the several layers includingthe reinforcing wires in the corrugated structure. From the foregoingdescription it is quite evident that reinforced layers such as shown inFIG. 7B and 7C, and 8B may be utilized as the outer layers in theformation of the corrugated structure by apparatus shown in FIG. 13 inplace of the extruders 199 and 205. In such a case the reinforced layerswould be preheated before being fed to the drums 197 and 204 in order toprovide adequate heat to effect a seal with the corrugated structure193. The utilization of outer layers 209 and 210 such as shown in FIG.7B and 7C and 8B would produce a resultant structure as illustrated inFIG. 13E. However, in the latter case it is generally not necessary touse longitudinal wires in the corrugated structure as the outer layersprovide adequate structural strength. For purposes of illustration, theplastic layers and wires have been exaggerated in thickness in FIGS. 13Ato 13E. FIG. 13E' illustrates the product of FIG. 13E with the relativethicknesses of the plastic layers and wires more precisely displayed.

It is evident that the various products thus far discussed andmanufactured in accordance with the invention may be utilized eitheralone or in combination with the other types of packaging materials inorder to meet a wide variety of needs in the packaging industry. Forinstance, the structure denoted by number 85 in FIG. 7C may be combined,as illustrated in FIG. 14, with a cellular material generally denoted bythe number 211 to provide a substantially rigid wall covered on at leastone side by the cushioning material. The cushioning material may takeany suitable form and may be a material such as illustrated anddescribed in U.S. Pat. No. 3,142,599. FIG. 15 illustrates a furthermodification of the invention wherein the layer 85 is combined with aplastic foam 212 formed of polyurethane or other suitable material. Itis evident that while the reinforced plastic layers 85 have beenillustrated in FIGS. 14 and 15 similar combinations may be made with thereinforced layers shown in other of the figures previously described.FIGS. 16 and 17 show still additional products which may be manufacturedin accordance with the invention. In FIG. 16 the structure as shown inFIG. 13E is combined with the cellular material 211 while in FIG. 17 thesame structure is combined with a plastic foam 212. It is, of course,evident that the structure of FIG. 13D may be utilized in place of thestructure of FIG. 13E and even a structure such as shown in FIG. 13C maybe utilized either in the manner illustrated or may be reinforced withlongitudinal or transverse wires.

In all of the embodiments of the invention illustrated and described itis evident that various types of materials may be utilized in theirfabrication. For instance, the reinforcing elements may be formed ofsteel having the desired carbon content and various steel alloys as wellas aluminum, copper and other similar metals may be utilized whichafford structural strength and rigidity. Lightweight metals such asmagnesium or even tungsten may be used where weight is a significantfactor. In connection with the plastic material polyethylene of variousdensities, polypropylenes and their copolymers, polystyrenes andpolyvinyl chloride may be employed, various polyesters and polyamidescan also be used. Thermosetting resins may also be employed for variousapplications such as modified and flexible phenolic resins, alsophenolformaldehydes, urea-formaldehydes, furfural-formaldehydes as wellas melamine-formaldehydes. In order to provide resistance to moisturevapor and other gases the plastic films utilized may be pre-coated witha film of polyvinylidene chloride or other similar relatively gasimpervious plastics. As previously mentioned the various productsproduced in accordance with the invention have been illustrated in mostcases with the thicknesses of the plastic and adhesive layers beingexaggerated in thickness for clarity. However, in each instance theplastic layers are usually about one-half the thickness of thereinforcing wires. It is also understood that the number of wires perinch, the thickness of the wires and the thickness and type of theplastic layers can all be modified to achieve the desired structuralstrength. Similarly, the arrangement of the reinforcing wires can alsobe selected to achieve the desired ends. For instance, when using bothlongitudinal and transverse wires in the layers overlying the corrugatedstructure it may not be necessary to use the longitudinal wires in thecentral corrugated structure. The term "wires" as used in thisapplication is intended to include wires of various cross sectionalconfigurations such as round, oval, flat, square and the like.

While only certain embodiments of the invention have been illustratedand described, it is understood that modifications, alterations andchanges may be made without departing from the scope and spirit of theinvention as defined in the appended claims.

What is claimed is:
 1. The method of forming a wire grid comprising thesteps of feeding successive transversely disposed wires onto a drum andretaining them in spaced parallel relationship, feeding a plurality ofspaced parallel longitudinally disposed wires into overlyingrelationship with said transverse wires, joining each longitudinal wirewith each transverse wire to form a self-supporting grid, corrugatingsaid grid to form crest portions on both sides thereof and then sealinga layer of plastic to the crest portions on at least one side thereof.2. The method according to claim 1 wherein said longitudinal wires arejoined to said transverse wires to form mechanical bonds.
 3. The methodaccording to claim 2 wherein said longitudinal and transverse wires arecoated with a plastic and said wires are heated to cause the plastic toadhere the wires one to the others at each intersection of thelongitudinal and transverse sets of wires.
 4. The method according toclaim 1 wherein said corrugating grid is preheated to effect a seal withsaid overlying layers.
 5. The method of forming a wire mesh according toclaim 1 wherein said longitudinal and transverse wires are coated with aplastic and said wires are heated to cause the plastic to adhere thewires, one to the others, at each intersection of the longitudinal andtransverse sets of wires.
 6. Apparatus for forming a wire reinforcedcorrugated structure comprising a drum having a plurality of axiallydisposed spaced arrays of wire receiving and holding means, means forsuccessively feeding axially disposed transverse lengths of wire ontothe surface of said drum with each wire engaging one array of receivingand holding means, means for feeding a plurality of longitudinallydisposed wires onto said transverse wires, means for effectingengagement of each of said longitudinal wires with each of saidtransverse wires to form a grid, means for corrugating said grid andmeans for adhering at least one plastic sheet to the crest portions onone side of said corrugated grid.
 7. Apparatus according to claim 6wherein said means for effecting engagement comprises a pressure rollerfor forming said longitudinal wires about each transverse wire. 8.Apparatus according to claim 6 wherein at least one of said sets ofwires is coated with a plastic and heating means for heating said wiresto the vicinity of the melting point of the plastic prior to engagementof one set of wires with the other.
 9. Apparatus according to claim 6wherein said grid is heated to a temperature at least equal to themelting point of said plastic layers and said feeding means includes apair of spaced belts each carried by a pair of cooled rollers and saidcorrugated grid and overlying layers of plastic are fed between saidbelts to embed the crest portions of the corrugated grid into saidplastic layers.